The use of anesthetic in tooth extraction is not necessarily produce side effects, side effects and the use of anesthetic in tooth extraction, the patient’s physical state, the doctor’s operation is related. 1, fainting: can be caused by fear and nervousness, fatigue, poor general health and other factors; 2, anesthesia poisoning, overdose reaction: the amount of local anesthetic is too large, the speed of injection can be caused by the local anesthesia, abnormal sensation, muscle tremors, convulsions, heart rate slowing down, cardiac arrhythmia and Cardiac arrest, coma and respiratory depression, etc.; 3, allergy or allergic reaction: manifested as erythema, itching, rash, angioedema, bronchospasm, dermatitis, respiratory difficulties, laryngospasm, shock, etc., but the likelihood of serious allergic reaction is relatively low; 4, nerve injury: injection of needles into the nerves or injected into the alcohol mixed with the drug can cause nerve pain, numbness or sensory abnormality, most of them are temporary, Most of them are temporary and reversible injuries, which can be cured by themselves, while a few of them last for a long time and even cannot return to normal.